High Mixing Rates Research Articles

Anciently Asexual Bdelloid Rotifers Escape Lethal Fungal Parasites by Drying Up and Blowing Away

Asexuality has major theoretical advantages over sexual reproduction. An important evolutionary puzzle, therefore, is why exclusively asexual metazoan lineages rarely endure. The Red Queen hypothesis posits that asexuality is rapidly extinguished by relentlessly coevolving parasites and pathogens. If so, any long-lasting asexual lineage must have unusual alternative mechanisms to deal with these biotic enemies. Bdelloid rotifers are freshwater invertebrates that abandoned sexual reproduction millions of years ago. Here, we show that cultured populations of bdelloids can rid themselves of a deadly fungal parasite through complete desiccation (anhydrobiosis) and disperse by wind to establish new populations in its absence. In Red Queen models, spatiotemporal escape can decouple and protect asexuals from coevolving enemies. Thus, our results may help to explain the persistence of the anciently asexual Bdelloidea.

Turbulent precipitation in micromixers: CFD simulation and flow field validation

The object of this work is the investigation of the process of nanoparticles turbulent precipitation in a micromixer, the Confined Impinging Jets Mixer. This study is motivated by the increasing importance that nanoparticulate systems have for applications in several fields and by the consequent necessity of developing an economical and reliable process for the production of nanoparticles with the desired qualities, in terms of size, morphology and composition. The precipitation process is among the most promising processes for this purpose, and micromixers, such as the CIJM, are employed because they provide high mixing rates and efficiencies, which are needed because the process is highly mixing sensitive. Here a precipitation model based on classical precipitation theory and Computational Fluid Dynamics was developed and tested on barium sulphate precipitation, which is often employed as a mixing sensitive test reaction alternative to parallel competitive reactions. The use of barium sulphate precipitation also allows to assess the capability of the CIJM of producing very fine particulate systems. The flow field is modelled with a RANS approach, and validated through comparison with experimental data, obtained with the microscopic Particle Image Velocimetry. Model predictions on barium sulphate mean particles size were compared with experimental data and good agreement was found.

A Controllable Twin- Fluid Internally Mixed Swirl Atomizer

The atomizer serves as an energy conversion mechanism to convert a volume of the liquid into a multiplicity of small droplets and then ejects these droplets so as to produce a high ratio of surface to mass in the liquid phase and thereby achieve high rates of mixing and evaporation. For the current needs, a compact configuration arrangement is needed to meet the design requirements of small volume and high maintenance availability. As compared with the traditional design, the new atomizer designs should possess better energy conversion efficiency (from pressure to kinetic energy). The technique of combining two or more principles has well served in the field of atomization in the past. The drawbacks of one type of atomizer can be overcome by combining it with other types of atomizer, in what is generally referred to as a hybrid atomizer. The atomizer discussed in this paper combines the principles of twin-fluid internally mixed atomizers and conventional pressure swirl atomizers to produce a spray the characteristics of which can be controlled over a wide range of operating conditions. Atomization of liquids is widely used in several applications, e.g. spray combustion, spray-painting, spray drying, crop spraying and many other applications. In some atomizer applications the control of droplet and/or particle size is very critical. In some applications, extremely small droplets are preferred (less than a micron), while in others, droplet diameters on the scale of several hundred microns are required. Spray combustion is used in domestic heating burners, industrial heating furnaces, gas turbines, diesel engines and rockets. For the different applications, a wide range of spray devices have been developed and they are generally designated as atomizers and nozzles (1-3). Spray may be produced in various ways. The process of atomization is a process where a liquid jet or sheet is broken up by the kinetic energy of the liquid itself or by exposure to high- velocity air or gas. Some atomizers accomplish this by discharging liquid at high velocity into a relatively slow-moving stream of air or gas. Examples of this type of atomizers include various forms of pressure atomizers and also rotary atomizers that eject the liquid at high velocity from the periphery of rotating disc. An alternative approach is to expose a relatively slow-moving liquid to a high- velocity air stream. This method is generally known as twin- fluid, air-assist or air-blast atomization. In the context of the present invention, it is worthwhile to mention about the conventional swirl atomizer and an internally mixed atomizer reported in the prior art. In swirl atomizer liquid is made to flow through a swirler before it exits from the atomizer, providing a tangential motion to the liquid. This swirling liquid forms a hollow cone outside the atomizer and this cone breaks up into droplets once the kinetic energy of the molecules of the cone overcomes the surface energy of the liquid. In an internally mixed atomizer, a small amount of gas is introduced into the liquid inside the injector forming a two-phase mixture of liquid and gas. This two-phase mixture produces liquid droplets owing to two-phase flow dynamics. However, due to the absence of any tangential velocity component in the flow (because it is a one dimensional flow), this atomizer always forms a solid cone spray.

Nano-emulsions prepared by the phase inversion composition method: Preparation variables and scale up

The aim of this work is to study, through experimental design, the effect of vessel geometry and scale-up in the properties of nano-emulsions prepared through the phase inversion composition method (PIC). Results show that a proper mixing is crucial for small droplet-sized nano-emulsions, especially when remaining free oil is found together with the key liquid crystal phase formed during the emulsification process. In these cases, mixing must be near the perfect mixed model. Proper geometries must be selected to promote a good mixture. Small addition rates V ad and high mixing rates ω promote the necessary mixing level. However, results indicate that, if free oil remains together with liquid crystal formed during emulsification, a too high ω could promote coalescence of oil droplets. When a cubic liquid crystal phase Pm3n is formed instead during emulsification, without free oil, coalescence is not promoted, probably due to the extremely high viscosity. For the system where Pm3n is formed during emulsification, scale-up cannot be done, as it would be expected, maintaining adimensional variables – Reynolds, Re, and adimensional time. A perfect correspondence between scales is observed when the total addition time and the lineal mixing rate are maintained between scales instead. Re, i.e. the ratio between inertial and viscous forces, does not seem adequate to describe the system, as inertial forces are worthless due to the extremely high viscosity.

Sudden infant death syndrome, population mixing and oil-related development in western Norway

ABSTRACTA number of features of sudden infant death syndrome (SIDS) point to an aetiological role for apparentlyminor infections. The spread of infections is influenced by the rate of contact between infectiouscases and susceptibles in the population. This is likely to differ geographically depending on patternsof social contacts, with epidemics being particularly likely where an influx of migrants leads to highrates of mixing of populations lacking herd immunity. It has been shown that geographical variationsin SIDS deaths in England and Wales are strongly associated with rates of long distance in-migrationinto districts. The large influx of population into parts of western Norway as a result of oil-related developmentprovides an opportunity to examine this issue further. The most intensive development hasbeen in the Stavanger area in the county of Rogaland. Published migration statistics show that therewas a rapid build-up of long distance migration into this area reaching a peak in the late 1970s. Furthernorth, the Bergen area in the county of Hordaland was little affected by oil-related activities in the1970s. However, the more recent development of oil provinces further north has led to more activity inthe Bergen area and an increase in in-migration from the mid 1980s onwards. Annual data from 1969onwards on SIDS deaths in Rogaland and Hordaland counties and for Norway were used to assesswhether trends in SIDS mortality and migration showed any associations. Before the main populationinflux Rogaland had a SIDS rate that was below the Norwegian average. However, since the mid1970s SIDS rates have been significantly in excess of the national average. In Hordaland SIDS rateswere low throughout the 1970s but increased substantially to be significantly in excess of the Norwegianaverage in the late 1980s. In both areas population influxes resulting from oil-related developmentwere therefore followed by a significant increase in mortality rates from SIDS. There is no evidencethat these trends can be accounted for by changing patterns of known risk factors for SIDS in theseareas nor of artefacts in the registration of SIDS cases. The results of this study therefore support theBritish evidence that population mixing may be a significant factor in the aetiology of SIDS.

Mixing on the continental slope of the southern Weddell Sea

Shipboard hydrography and current profiles collected in 2003 and time series from moored current meters deployed in late 1990s are analyzed to study the variability of mixing in the southeastern Weddell Sea. Profiles of eddy diffusivity Kρ are inferred from fine‐scale shear (vertical derivative of horizontal velocity) and strain (vertical derivative of isopycnal displacement) variance using parameterizations which relate the internal wave energy to the dissipation rate at small scales. The highest mixing rates are seen near the bottom where the eddy diffusivities are elevated by 1 order of magnitude from those in the interior and exceed 10−4 m2 s−1. The observations show latitudinal variability in Kρ, particularly near the bottom, where Kρ significantly increases near 74° 28′S, the critical latitude for lunar semidiurnal (M2) tides. In this region, the critical latitude coincides with near‐critical topography on the upper continental slope, a situation which favors generation of M2 internal waves. Consistent with the results from fine‐scale shear and strain parameterizations, which indicate highest bottom diffusivities near the critical latitude, independent analysis of current time series from moored instruments shows a thickening of the frictional bottom boundary layer near the critical latitude. Semidiurnal tidal dynamics at the upper continental slope together with the critical latitude effects lead to mixing that might significantly affect the regional heat budget and the circulation in the study area.

Turbulent supply of nutrients to phytoplankton at the New England shelf break front

We present observations from deployments of a microstructure turbulence instrument (the Towed Microstructure and Auxiliary Sensor Instrument) aboard a pumping profiling vehicle (the Lamont Pumping SeaSoar) towed behind a research vessel at the New England shelf break front in August 2002. From these we determined coincident fine‐scale vertical eddy diffusivity and gradients of nitrate, phosphate, and silicate on several transects spanning the front. We then quantified vertical turbulent nutrient fluxes through the base of the euphotic zone (defined as the 1% light level), the base of the density transition zone, maximum nutrient gradients (the nutriclines), and the depth of maximum stratification (the pycnocline). Vertical eddy diffusivity estimates spanned a wide range from near‐molecular levels at the pycnocline to values exceeding 10−3 m2 s−1 at depth and in the surface layers. Vertical nutrient fluxes were maximal at the 1% light level and decreased by 2 orders of magnitude as they moved upward through the water column to the depth of the pycnocline. Nutrient fluxes were enhanced shoreward of the front because of high mixing rates and nutrient gradients at the depth of the 1% light level. Nitrate fluxes there averaged about 6 × 10−5 mmol N m−2 s−1, sufficient to support a net community productivity of 30 mmol C m−2 d−1. Seaward of the front, these fluxes averaged about 1 × 10−5 mmol N m−2 s−1 and would support correspondingly lower productivity. A small part of the upward flux appeared to support a silicifying community of phytoplankton that consumed phosphate in proportion to nitrate at about double the canonical Redfield stoichiometry.

Flow Control of Jet Flow by Passive Nozzle Configuration Changes

Nozzle configuration may offer the possibility of a passive control technique to provide high mixing and heat transfer rates. Thus, numbers of investigations have been carried out to reveal the influence of nozzle configuration on the flow characteristics. However, very few papers in the scientific literature have focused on orifice jets. Despite the evidence indicating that orifice jets improve the mixing and heat transfer characteristics, we were unable to find a systematic study of them that focused on the contraction area ratio. The effects of varying the contraction area ratio CR from 1.00 to 0.11 on the flow characteristics of a free jet issuing from an orifice nozzle were examined. The large vortex structure of a submerged orifice water jet was visualized by the tracer method, which indicated the coherent vortex structure was highly affected by the CR value. The mean and fluctuating velocities of the orifice air jet were also measured using a single hot-wire and the effects of CR on them were demon...

The spatial and vertical distribution of living (stained) benthic foraminifera from a tropical, intertidal environment, north Queensland, Australia

We investigated the distribution of living (stained) benthic foraminifera across a tropical, intertidal shoreline adjacent to Cocoa Creek, Queensland, Australia for the purpose of better understanding the nature of test production and ultimately fossil assemblage development within such environments. Short cores (up to 1 m) were collected during the wet and dry season, along an elevational gradient comprising non-vegetated intertidal mudflat and higher-intertidal mangrove forest environments. The distribution of stained specimens can be broadly delineated into assemblages characterising ‘upper mangrove’ (2.64–2.91 m above Lowest Astronomical Tide (LAT)) and ‘low mangrove-mudflat’ (1.62–2.18 m above LAT) environments. Agglutinated species were generally limited to upper mangrove stations. Calcareous species occurred within all of the intertidal environments examined but differ in their composition between upper and lower intertidal settings. Upper mangrove faunas were characterised by the agglutinated species Arenoparrella mexicana, Haplophragmoides wilberti, Miliammina fusca, Miliammina obliqua and Trochammina inflata and the calcareous species Helenina anderseni. Live (stained) assemblages at lower intertidal elevations were dominated by the calcareous species Ammonia aoteana, as well as Rosalina spp., Elphidium oceanicum, Triloculina oblonga, Ammonia pustulosa and Shackoinella globosa. Absolute densities of stained specimens were lowest within the low mangrove sediments (6–8 specimens per cm 2) but higher within the upper mangrove (25–249 specimens per cm 2) and mudflat (8–77 specimens per cm 2). Abundances within mudflat sediments varied seasonally (being significantly larger in the wet season) whereas those within mangrove zone sediments changed little through the year. Stained foraminifera were found to a maximum depth of 50 cm at Cocoa Creek, extending to the greatest depth at the upper mangrove stations, and were generally shallowest beneath the lower mangroves. All stations had over 50% of their foraminiferal standing crop below the upper 1 cm, although at most stations < 10% of living specimens occurred within this layer. Comparison of this data with dead assemblages suggests that: (1) abundances of stained specimens, averaged over two sampling events, reasonably approximate aggregate in situ test production; and (2) a clear enrichment of infaunal species occurs within the mangrove. The latter effect was less conspicuous on the mudflat due to high rates of mixing and assemblage time-averaging, which obscure the signal of test production within the dead assemblages. In both cases, the validity and stratigraphic resolution of surface assemblages for sea-level and other palaeoenvironmental reconstructions is questionable.

Cadmium Biosorption on Vegetal Biomass

Effective removal of heavy metals from wastewater is one of the most important environmental challenges facing the world. Various techniques are used to remove the metals. Biosorption has gained credibility in the last decade because of its good performance and low cost. The objective of this study is to explore the use of olive pits for cadmium wastewater removal. The effects of mixing rate, pH, particle size, biomass and initial concentration and equilibrium metal ion concentration are evaluated. Results indicate nearly linear uptake by the biomass with increasing initial cadmium concentration. Adsorption increases rapidly in the pH range of 3-9, then levels off. Cadmium concentration uptake increase with increasing biomass concentration until reaching 5 g/L. Mixing rates up to 250 rpm increase uptake, however, higher mixing rates result in a vortex that incorporated air into the mixture, this resulted in a decrease in uptake. The adsorption isotherm appears to follow the Langmuir model.

A Controllable Twin- Fluid Internally Mixed Swirl Atomizer

The atomizer serves as an energy conversion mechanism to convert a volume of the liquid into a multiplicity of small droplets and then ejects these droplets so as to produce a high ratio of surface to mass in the liquid phase and thereby achieve high rates of mixing and evaporation. For the current needs, a compact configuration arrangement is needed to meet the design requirements of small volume and high maintenance availability. As compared with the traditional design, the new atomizer designs should possess better energy conversion efficiency (from pressure to kinetic energy). The technique of combining two or more principles has well served in the field of atomization in the past. The drawbacks of one type of atomizer can be overcome by combining it with other types of atomizer, in what is generally referred to as a “hybrid atomizer”. The atomizer discussed in this paper combines the principles of twin-fluid internally mixed atomizers and conventional pressure swirl atomizers to produce a spray the characteristics of which can be controlled over a wide range of operating conditions.

Estimating in situ phytoplankton growth rates with a Lagrangian sampling strategy

Quantification of biogeochemical rates is essential to the understanding of the dynamics of aquatic ecosystems. However, this has proven to be difficult to achieve especially under conditions of high spatial and temporal hydrodynamic and biogeochemical variability. Here, a Lagrangian experimental design was employed to estimate biogeochemical rate coefficients in situ. A set of four drogues and a cross‐transect sampling design was used to capture the patchy distribution of phytoplankton and nutrient species, and high transport and mixing rates. A mass balance approach was applied to a Lagrangian control volume moving with a drogue. This approach was used to separate internal biogeochemical changes from the physical changes due to advection, diffusion, and convergence/divergence fluxes. This experimental approach was applied to an oligotrophic coastal region. The phytoplankton growth rate, primary production, and carbon to chlorophyll ratio (C:Chla) obtained from the experiment agreed with the highest literature values for this study site. This supported the validity of this approach. The effect of scales of processes and patchiness is highlighted from this experiment. It is shown that the experimental design is subject to a relationship between size of the control volume, the time scale of internal processes, and sampling time.

Experimental Investigation of a Pressure Swirl Atomizer Spray

The fuel injector has an important role in the process for an efficient combustion because it increases the specific surface area of the fuel and it allows one to reach high rates of mixing and evaporation. This paper has focused on the behavior of kerosene Jet A-1 spray produced by commercial pressure swirl atomizers in terms of mean diameter distributions, velocity component profiles, and cone angle variations over time. The analysis has been carried out experimentally with the aid of a phase-Doppler anemometer system, which provides drop sizes and velocities. The fluctuating behavior of the spray has been analyzed also with a fast imaging technique by means of a high-speed charge-coupled device camera. The instantaneous spray cone angle, estimated with a digital image analysis, has shown that the average cone angle roughly equals the one calculated with phase-Doppler anemometer data, and that it is different from its nominal value. A preliminary investigation into the frequency domain has shown two oscillation modes at low frequency around 100 Hz and at high frequency around 1800 Hz. This issue is a key result because spray oscillations affect the flame stability and the resulting combustion efficiency because a change in the local air/fuel mixture ratio is induced.

Predicting the Displacement of Yoghurt by Water in a Pipe Using CFD

AbstractA numerical scheme based on the volume of fluid (VOF) method for predicting the displacement of one liquid by another has been verified versus electrical resistance tomography (ERT) and ultrasonic velocity profile (UVP) measurements for the displacement of yoghurt by water. The scheme using the VOF method predicts the skewed phase distribution as measured using ERT and the global structure of the velocity profile as measured using UVP. The phase distribution using the VOF method was compared with the results using the species transport model which allows for mixing between the phases. The species transport model was found to be less suitable for predicting the displacement of yoghurt by water since the turbulence model was unable to accurately predict the turbulent viscosity in the mixing zone between yoghurt and water, which resulted in a too high rate of mixing.

Rapid vertical mixing rates in deep waters of the Andaman Basin

The Andaman Basin is an enclosed region in the northeastern Indian Ocean with its deep water below approximately 1800 m almost isolated with respect to horizontal ventilation by the Andaman-Nicobar Islands separating it from the Bay of Bengal. The physical and chemical properties including radiocarbon ((14)C) measured at two stations of the Andaman Basin show negligible variation with depth in the waters below 1300 m, indicating a well-mixed water mass. This study attempts to derive the mixing rates for deep waters of the Andaman Basin. Model calculations based on (14)C profile measurements indicate rapid vertical mixing (vertical advection velocity, w>200 m year(-1)) in waters deeper than 1800 m of the basin. For a basin with deep water thickness of 1000 m below 1800 m, deduced mixing rate of >200 m year(-1) translates to mixing time of <5 years. As shown for other regions, the possible mechanism responsible for such high vertical mixing rates could be the internal waves generated from tidal currents flowing through rough topography. In addition, Andaman Basin is underlain with a young crust and is known for its high heat flow, which also could contribute to the high vertical mixing.

Contrasting the vertical differences in the phytoplankton biology of a dipole pair of eddies in the south-eastern Indian Ocean

Abstract A dipole pair consisting of one warm-core (WC) and one cold-core (CC) eddy formed off Western Australia in the winter of 2003. Within these eddies the vertical distributions of phytoplankton, both in terms of community and physiology, were characterized in an effort to understand the impact of eddies on the phytoplankton ecology of the region. The WC eddy had a 275-m deep mixed layer in the centre and a vertically dispersed photoautotrophic community dominated by large diatoms, Pelagophyceae and coccolithophorids. The CC eddy had a shallower and more consistent mixed-layer depth with a deep chlorophyll a maximum (chlamax) well developed throughout the eddy. The euphotic zones and mixed layers of both eddies were very low in nitrate. Phytoplankton characteristics that are known to acclimate to variation in irradiance but require different amounts of time to reach steady state were measured at the surface and deep chlamax in both eddies. Differences between the surface and chlamax were found for characteristics that can diverge over a range of time scales from very short (seconds) to much longer (months) for physiological and ecological parameters such as: Ik and fluorescence quantum yield from PAM fluorometry, pigments (photoprotective and photosynthetic), pigment ratios, carbon to chlorophyll a ratios, PB and PBmax (measured over 24 and 4 h, respectively) community composition based on cell counts and pigments, and deep chlamax formation. Absolute time scales for change of these characteristics were obtained from the literature and used to quantify vertical mixing rates in the two eddies. Overall, vertical mixing is shown to be more pronounced, up to 20 times faster and deeper, in the WC eddy than in the CC eddy, especially near the WC eddy centre. This high rate of vertical mixing is hypothesized to allow the development and persistence of a vertically homogeneous community of large diatoms that spreads from the surface down to 275 m, well below the euphotic depth. As nitrate concentrations in the surface mixed layers of both eddies were very low there was no capacity for a significant increase in phytoplankton biomass within the eddies without additional nitrogen inputs. The longer-term biological trajectories of the eddies are discussed.

Biodiesel Production Using Static Mixers

Static mixers, devices used for mixing immiscible liquids in a compact configuration, were found to be effective in carrying out initial transesterification reactions of canola oil and methanol. The objective of this study was to explore the possibilities of using static mixers as a continuous-flow reactor for biodiesel production. Biodiesel (canola methyl ester) was produced under varying conditions using a closed-loop static mixer system. Sodium methoxide was used as the catalyst. Process parameters of flow rate or mixing intensity, catalyst concentration, reaction temperature, and reaction time were studied. A full-factorial experimental design was employed, and samples were analyzed for unreacted glycerides as an indicator for biodiesel quality control. It was found that static mixers can be used for biodiesel production. In fact, given enough residence time, appropriate temperature, and high mixing rate, a reactor could consist solely of static mixers and pumps in a continuous-flow design. Temperature and catalyst concentration had the most influence on the transesterification reaction. The data clearly indicates separate inverse linear relationships between temperature and catalyst concentration verses total glycerin. The ASTM D6584 specification for total glycerin (0.24% wt, max.) was met at three of the four temperatures tested, utilizing two of the four catalyst concentrations. The most favorable conditions for completeness of reaction were at 60C and 1.5% catalyst for 30 min.

Electrical Conductivity and pH Prediction in a Recirculated Nutrient Solution of a Greenhouse Soilless Rose Crop

ABSTRACT The influence of nutrient solution (1) mixing rate, and (2) time of use on pH and electrical conductivity (EC) of a recirculated nutrient solution used for the irrigation of a greenhouse soilless rose crop was studied. Measurements of microclimate variables, pH, and EC of nutrient solutions and crop transpiration were conducted. The measurements of pH and EC values of nutrient solutions mixed with different mixing rates and applied for crop fertigation were used to develop and calibrate a model for pH and EC prediction in relation to nutrient-solution mixing rate and time of use. Application of the calibrated model gave satisfactory results. It was found that nutrient solutions with high mixing rates or volume equal to or double that of the total water consumed by the canopy during the conservation period had the most stable EC evolution and minimal pH changes.

Characteristics of Dual Transverse Injection in Scramjet Combustor, Part 1: Mixing

The mixing characteristics of a dual transverse injection system in a scramjet combustor were studied with numerical methods. The effects of the jet-to-cross-flow momentum flux ratio and the distance between injectors on mixing characteristics were investigated. Three-dimensional Navier–Stokes equations, including the k–! SST turbulencemodel,weresolvedwiththe finitevolumemethodadoptingtheupwindmethodofEdwards’lowdiffusion flux splitting scheme. It is shown that the mixing characteristics of a dual transverse injection system are very differentfromthoseofasingleinjectionsystem.Therearinjection flowisstronglyinfluencedbyblockageeffectsdue to the momentum flux of the front injection flow and thus has higher expansion and penetration than the front injection flow. The dual injection system has a higher mixing rate and a higher penetration but have more losses of stagnation pressure than the single injection system. It is also shown that there is an optimal distance between injectors for mixing characteristics and that the optimal distance increased as the jet-to-cross-flow momentum flux ratio increased.

Microwave Induced Jet Boiling Investigated via Voltammetry at Ring−Disk Microelectrodes

High intensity microwave radiation is (self-)focused at metal electrodes immersed in aqueous electrolyte solutions to generate highly localized superheating and convection effects. It is shown that, for an electrode pointing downward, low intensity microwave radiation causes density driven convective flow (upward), which at the onset of boiling abruptly switches to a fast jet of liquid moving away from the electrode surface (downward). This "jet-boiling" phenomenon allows extremely high rates of mass transport and mixing to be realized at the electrode surface. Cyclic voltammograms obtained at electrodes placed into a microwave field show very strong mass transport enhancement effects. Cyclic voltammograms recorded at a Pt/Pt ring-disk electrode system (r(1) = 25 microm, r(2) = 32 microm, r(3) = 32.4 microm) in the presence of microwave radiation are employed to further explore mass transport effects under microwave conditions. Mass transport coefficients, collection efficiencies, and temperatures are determined as a function of microwave intensity.